The invention relates to a machining tool, which is also suitable for high-speed machining in a metal cutting, for which at least one cutting body is held by a clamping organ in a plate seat of a tool holder, which is bounded only by a back pressure supporting surface and by a supporting surface, the supporting surface for the clamping organ and the supporting surface of the plate seat enclosing an angle, which exceeds the automatic interlocking and opens up to the back pressure supporting surface.
Different embodiments of such machining tools have already become known. In this connection, the basic aim has been to construct the tool of the fewest, self-secured components possible, which is necessary, for example, for high-speed processing.
The design always becomes a problem whenever very small tool dimensions are desired and when the cutting body is clamped instead of being soldered, so that it can simply be exchanged in case of need. In these cases (see, for example, Offenlegungschriften DE 33 43 448 A1 and DE 34 10 284 A1), exact positioning of the cutting body is required for metal cutting especially in the case of rotating processing machines, so that it very simply comes to be in precisely the same position once again even when exchanged or after wear. If a tool is to be created, which can be used on rotating processing machines in metal cutting for a large number of tasks, such as the cutting of annular grooves, the use with side milling cutters and circular milling cutters working on three sides, the end processing with integrated drills or multi-blade counterbores and drilling tools, reaming tools or the like, main and subsidiary cutting edges of the cutting body must come to lie freely in the plate seat of the tool and can automatically lie in contact only with the supporting surface and the back pressure supporting surface in the tool. All other sides must remain free. This, in turn, naturally makes the exact positioning in the longitudinal direction of the cutting edge more difficult.
It is therefore an object of the invention to configure a tool of the type named above in such a manner, that the cutting body can be shifted in the clamped state precisely adjustably on the plate seat.
Pursuant to the invention, this objective is accomplished owing to the fact that the cutting body is provided with a groove, which is engaged by a sliding pin, the diameter of which corresponds essentially to the width of the groove and which is disposed eccentrically and parallel to the axis of rotation of a bearing bolt, which is mounted rotatably in a bearing opening of the tool holder, passing through the supporting surface and/or the back pressure supporting surface, and which can be actuated from the outside.
The inventive construction results in an exact, locked coupling of the cutting body with the sliding pin, which is disposed eccentrically on a bearing bolt. If the bearing bolt is twisted about its longitudinal axis, the sliding pin, which is integrally molded or fastened to it eccentrically, shifts the cutting body into the one or the other direction parallel to the cutting edge. In this way, with the cutting body clamped within the scope of the eccentricity of the eccentric bolt, consisting of the bearing bolt and the sliding pin, the position of the cutting body on the plate seat can be changed and, on the other hand, this position can also be locked reproducibly in the set position by the sliding pin.
In a further development of the invention, it is possible to dispose the groove, which in this case is preferably bounded at both ends, in the bottom surface of the cutting body in contact with the supporting surface or, what is generally preferred because of the greater distance of the groove from the cutting edge and, with that, the higher load-carrying capability of the cutting body, to dispose the groove in the back surface of the cutting body, which lies in contact with the back pressure supporting surface. In this case, it can be constructed so as to be bounded at the top in order to increase the stability.
The axis of the bearing bolt advisably extends essentially parallel to the back pressure supporting surface of the tool in a plane, approximately perpendicular to the supporting surface. Due to the perpendicular position of the axis of rotation of the bearing bolt to the supporting surface, the sliding pin can dip completely into the groove. Preferably, the bearing bolt extends as far as directly below the supporting surface, so that an excessive bending stress on the sliding pin cannot occur during the twisting of the bearing bolt.
In order to hold the bearing bolt in the bearing opening so that it cannot be shifted axially but, nevertheless, can be rotated, provisions can be made in accordance with a further distinguishing feature of the invention so that the bearing bolt has an annular recessed groove, into which an axially delimiting pin protrudes. By unscrewing the axial delimiting pin, the bearing bolt, with the thereon adjoining eccentric sliding pin can very easily be removed upward or downward out of the tool holder.
To actuate the inventive, eccentric bolt, the bearing bolt, at its end remote from the sliding pin, may be provided with a hexagonal recess or the like for applying an actuating tool, such as a hexagonal sockethead cap wrench.
Aside from this construction of the bearing bolt as a smooth cylindrical pin (interrupted only by the annular insertion groove for the axial limitation), provisions can also be made so that the bearing bolt is constructed as a threaded bolt and its bearing opening is constructed in the tool holder as a borehole with an internal thread. In this case, also, an annular insertion groove may be provided, into which an axially delimiting pin protrudes. In this case, however, the width of the annular insertion groove must be larger than the diameter of the axially delimiting pin, in order to make possible an axial displacement of the threaded bolt corresponding to the axial clearance. The fact that, when the eccentric bolt is rotated, the sliding pin not only is rotated eccentrically with the bearing bolt, which is constructed as a threaded bolt, but also shifted in the axial direction, does not affect the adjustment of the cutting body, as long as it is ensured that the face end of the sliding pin cannot collide with an upper covering boundary of the groove.
In the case of the preferred construction of the clamping organ for holding the cutting body in its plate seat by a clamping action as a clamping shoe, provisions can be made in a further development of the invention so that the clamping shoe is provided at the end, remote from the plate seat, with a recess, which is engaged by a sliding locking pin, such as a lug, at the tool holder. This has the advantage that, when the cutting body is shifted in the plate seat, with the clamping shoe clamped tight, the clamping shoe is not swiveled along with the displacement of the cutting body and, instead, is held fast so that the clamping shoe must glide correspondingly over the supporting surface of the holder for the cutting blade.
Finally, it is also still within the scope of the invention to direct the axis of the clamping screw obliquely inwards into the tool holder. Especially for side milling cutters and circular milling cutters, this offers the advantage that a larger number of cutting bodies can be disposed at the periphery of the disk-shaped tool holder.
Further advantages, distinguishing features and details of the invention arise out the following description of an example, as well as out of the accompanying drawings.